Often, people seek information by asking their social contacts and by navigating their social network. This way of seeking information is still very popular in spite of the availability of vast repositories of information such as the world wide web, libraries etc. This is because people may possess unique information (e.g., location specific, or temporal), which is not easily available from other information repositories such as the Internet.
Wireless technology has made tremendous advances and there now exist a variety of access technologies for different needs. For example, cellular networks provide ubiquitous voice communications and some limited data services. Wireless LAN standards such as IEEE 802.11 have enabled un-tethered, high speed access to the Internet. In addition, Bluetooth™ has emerged as a cable replacement technology for providing low rate services between different kinds of devices.
Recently, there has been a convergence in devices, meaning that all these different technologies are available on a single device. For example, there are several cell phones on the market which are capable of Bluetooth™ communications. Recently HP™ announced a device which has cellular, Bluetooth® and WLAN capabilities. There has been some research on exploiting this convergence to provide better data and voice services. For example, an architecture which uses multi-hop communications to relay data to a cellular base station has been proposed. The rationale being that, reduced power used for multi-hop transmissions will result in improved spatial reuse and thereby provide better capacity in the network. Most research in ad hoc networks however adheres to the traditional point to point communication paradigm whereby the goal is to provide reliable end to end delivery of packets between a source and a destination (or multiple destinations in the case of multicast). The research has focussed on importing this traditional communication paradigm into the world of peer-to-peer wireless networks (or ad hoc networks).
There has been intense research effort in designing efficient routing and transport protocols that will enable traditional communication networks applications such as file transfer, voice and streaming applications. However, in a social network, people navigate or query for information by directly asking their friends or people in their vicinity. These social contacts then either provide an answer or direct the query to people whom they believe know the answer. In other words, there is no end-to-end notion of a communication session. Another proposed system involves peer-to-peer (P2P) networks in the wired/wireless world. In current P2P networks, the requestor sends a query which is propagated through a specific community (say Napster™) and if a match is found, the response is routed back to the requestor and a match is made. If, however, the requester is unavailable or has temporarily disconnected, the match is lost. If desired, the requestor must re-initiate the search.
7DS [M. Papadopouli and H. Schulzrinne, “Effects of power conservation, wireless coverage and cooperation on data dissemination among mobile devices”, ACM SIGMOBILE Symposium on Mobile Ad Hoc Networking & Computing (MobiHoc) 2001, Oct. 4-5, 2001, Long Beach, Calif.] is a peer-to-peer resource sharing system, aimed at providing data access to wireless mobile devices. As an example, consider a network of hosts which can communicate over a wireless local area network. Some of these hosts are able to access the internet via a wireless mode, an access point, or Bluetooth™. Consider host A who is participating in an internet access session but has intermittent connectivity to the internet. When A needs access but is not connected, it queries hosts in its proximity for the data. Suppose, hosts B and C receive the query. If they have the data, they can forward it to A. If they do not have the data, but they have internet access, they can obtain the data and then forward it to A. The emphasis of 7DS is data access provision for wireless mobile users who have intermittent connectivity. 7DS has its primary goal providing data connectivity to mobile hosts. In other words 7DS provides access to existing electronic resources.
The infostation concept, originally proposed by researchers at WINLAB [Do we have a non-web reference to WINLAB?], is based on the idea of using high power base stations (i.e., infestations) to provide high data rate network access to small geographically disjoint areas. The intuition is that users buffer large data until they are in the vicinity of an infostation, thereby incurring a delay. This leads to a natural delay-capacity tradeoff. The SWIM concept extends the infostation idea further by allowing data to travel towards the infostation by hopping through an intermediate mobile ad-hoc network.
SWIM incorporates the idea of propagating data throughout a network of mobile wireless devices. The main aim of SWIM (as with 7DS) is network access, meaning that devices generate data to be offloaded to the wired network through an infostation.
Dodgeball.com and Bedd.com are two examples of services which exploit the recent paradigm of social networking via mobile devices. They follow a number of companies, such as friendster.com and orkut.com, which enable virtual social networking through the internet. Like friendster.com and orkut.com, the Dodgeball.com service allows users to register a list of buddies. Now whenever the user is in a particular place, say a pub or nightclub, he uses his mobile phone to inform Dodgeball.com, who then informs the users' buddies within a ten block radius and also informs the user if his buddies are in the area. The Bedd service allows users with Bluetooth® enabled phones to enter profiles into their phone and search profiles on strangers mobile phones. If there is a match in profiles, the users are alerted. These profiles can contain application specific information, such as for dating or buying and selling products. However, since the queries propagate only through the mobile ad-hoc network, it is not possible to engineer the system to offer sharp service guarantees.
Querying for information over a wireless sensor network has also been investigated. The network consists of a regular grid of sensors in a unit area, in which each sensor can communicate only with adjacent neighbors. In addition, the nodes do not have directional information either about their neighbors or any other nodes. The problem considered is one in which a querying node transmits a query for some information from an unknown destination node. The basic tool in this work is that of random walks and more specifically the continuous time random walk (or Brownian motion). It considers several search strategies. In the first type, the source transmits a query, which does a random walk until it hits the destination. In the second type, both the source and destination transmit a query, and both do random walks until their paths intersect. In the third type, the destination periodically caches the information and the source simply does a random walk until it hits one of the caches. The analysis in that proposal relies heavily on results from random walks and intersections of random walks. The assumption of continuous random walks may not be valid in real-world scenarios.
It is with the knowledge of the above mentioned systems and issues that the present invention has been made and is now reduced to practice.